Theftproof device for watt hour meters



Feb. 23 1926. 1,574,039

F. A. KOLB THEFTPROOF DEVICE FOR WATT HOUR METERS Filed May 23, 1924 Patented Feb. 23, 1926.: I

: umTEo FSL'IIATES PATENT "OFFICE.

1mm A. 301.3, or HAMMOND, .mnmna,.ass1onon or ONEeHALF T MORSE.

' DELLPLAIN, or HAMMOND, INDIANA.

THEFTPBOOF DEVICEFOR WATS. HOUR application filed m 23, 1924. Serial No. 715,398.

To all whom it may concern:

Be it known that I, FRANK A. KoLB, a citizen of the United States, and a resident of Hammond, county of Lake, and State of Indiana, have invented certain new and useful Improvements. in a Theftproof Device for Watt Hour Meters, of which the followin is a specification. v

y invention pertains to a theft-proof device'for watthour meters, and the object of this invention is to providemeans for preventing the theft of electric current in installations using watthour meters; and another object is to provide means in connection with a watthour meter, so arranged that any attempt to insert a wire from the line terminal to the load terminal of the watthour meter will cause a short circuit, thereb blowing the line fuse.

Wit the useof a watthour meter theft of current is frequently resorted to and is usuallyaccomplished by inserting one end of a; wire in the line terminal of a watthouse meter and the other end of a wire in the load terminal, .thereby shunting the current coil of the meter and allowing the use of unmetered current. I prevent such theft with my invention, by replacin the bushing and terminal which is connected to the load side of the current coil of the of the meter, with a special bushing and terminal, and connecting this terminal electricall to a oint which will give a part of sai Q s ecia terminal an electrical poten tial whic is the opposite to the electrical potential vof the mam part of said terminal. Other objects willappear hereinafter.

- The invention consists in the combinations and arrangements of 'parts hereinafter described and claimed.

The invention will be best understood by reference to the accompanying drawings forming a part of this specification, and m Fi 1 is a partial elevational' view of a watt our meter with my invention mounted in position thereon;

Fig. 2 is a detail view of the assembly; V

Fig. 3 is a planview of my invention;

- Fig. ,4 is a vertical sectional view taken terminal Said terminal 24=is preferably rect Fig.5 is a horizontal sectional view taken hour meter w ich includes the glass disk.

10 and the terminal boxll with its terminal chamber 11. In this chamber 11' of the terminal box I mount my improved device D, by replacing a bushing and terminal on the load side of the meter, and connecting my device with the load wire 12 and with the line side of the current coil of the meter; and other load terminal and bushing '13 with its connected load wire 14, and the line terminals andbushings 15 and 16 With the connected negative and positive line wires 17 and 18, being retained, as indicated in Fig. 1. p

My improved device comprises a main insulatin bushing 20 with a channel extending t erethrough which-is smaller at its lower end'21, to form a shoulder 22, upon which is seated a metal ring 23, preferably of copper, and a main terminal 24 is mounted above said ring and insulatedtherefrom by a fiber washer 25. A chamber 26 is provided in said terminal 24 and a screw 2T extends through the walls of said main bushing and said terminal to press and retain the exposed metal end 12 of load wire 12 againstthe inner terminal wall in chamend and the insulation being retained around said wire extending through ring 23 and through the restricted o ening. 21. attened at opposite sides 24' to readily assume the corosition in its bushing 20. Said main terminal has an upper lug 28 with a terminal screw 29 anda washer 30 for con necting said terminal in the usual manner to the load side of the currentcoil (not shown) of the meter.

Means is provided for electrically connecting a part of my improved terminal device, as a copper ring 23, to a point which has a potential opposite tothe potential of said terminal device, and preferably to a. point on the line side of said meter, which will give said part or ring a. potential opposite to the potential of the main part of said terminal device. This means preferably comprises a terminal assembly including a metal sleeve 30 carrying a metal stem 31 which is threaded into an opening in ring 23, while an insulating bushing 32 surrounds said sleeve and is mounted in the main bushing 20. An insulated copper bar 33 has its exposed end 33' fastened in said sleeve by a binding screw 34 threaded in the sleeve, and has its opposite end electrically connected with the negative line terminal 15, as by means of a binding screw 35. The device is so placed in the meter that both connections of bar 33 are within the terminal box 11, and thus out of reach and out of view when said box is closed. I I

In equipping an installed meter with my device, or in installing a meter equipped with my device, the insulation of the load wire is removed only far enough from the end of the wire to make contact with the new terminal 24. This allows the insulation on the load wire to extend through the ring and prevent contact between the ring and the load wire, and the ring is made of such a diameter that it merely permits the insertion of a shunt wire between said ring and said load wire, and only by making contact between the inserted shunt wire and the ring, thus making it impossible to make an additional electrical contact with the terminal 24, without first making contact with the ring 23 With this mechanical arrangement of the parts, any attempt to insert an electrical conductor, extending from the line terminal to the load terminal will result in a short circuit, thereby blowing the line fuse. If an electrical conductor is inserted in the load terminal, so as to contact with the actual terminal or main terminal 24, a short circuit will result between the copper ring and said actual terminal. And this device can either be incorporated in the manufacture of watthour meters, or it'can be'inserted'in existing meters by replacing one of the load terminals withmy improved device and attaching the device electrically to the line germinal of opposite potential, as shown in While I have illustrated and described the preferred form of construction for carrying my invention into effect, this is capable of variation and modification without depart ing from the spirit of the invention. I, therefore, do not wish to be limited to the precise details of construction set forth, but

desire to avail myself of such variations andmodifications as come within the appended claims.

Having described my invention, what I claim as new and desire to secure by Letters Patent is: 4

'1. In an electric meter, a device of the scope of the character described comprising a bushing with terminal members therein insulated from each other, and means for connecting one of said members to a point in said meter of different potential than the other of said terminal members, to prevent theft of current from said meter.

2. In an electric meter, a device comprising a bushing with terminal means therein, a part of said terminal means in said bushing being insulated from the main terminal portion, means for connecting said part to a point in said meter which will give said part the opposite electrical potential from the main terminal portion and will prevent shunting of the current coil of the meter.

3. In an electric meter, a device of the character described comprising a main terminal with a bushing, metallic means in said bushing and insulated from said main terminal, and electricity conducting means connecting said metallic means with a point of opposite potential to the main terminal to terminal, said metallic means and entire device being arranged to prevent connecting said terminals by a shunt wire and to prevent the theft of current.

5. In an electrical meter, a terminal box with line terminals and load terminals and terminal wires connected thereto, one of said terminals comprising a bushing, a main terminal member mounted in said bushing, a metallic member mounted in said bushing and insulated from said main terminal member an insulated terminal wire extending from said main terminal member through said bushing and being only slightly spaced from said metallic member to cause a shunt wire to engagesaid metallic member when inserted in said bushing, and electricity conducting means in said terminal box extending from said metallic member through said bushingand joined to another of said terminals to prevent theft of current from said meter.

6. In a watthour meter, a device comprising a terminal with a bushing, a metal ring in said bushing and insulated from said terminal, a terminal wire extending from said terminal through said ring and being insulated therefrom, said ring being slightly larger than said insulated wire to engage a shunt wire that may be inserted between said insulated wire and said ring, and electricity conducting means extending from said ring to a point of opposite potential from said terminal.

7 In a watthour-meter, a device comprising a main terminal with a bushing, a metal member in said bushing and insulated from said terminal, an auxiliary terminal removably mounted on said member and extending from said bushing, and current conducting means connecting said auxiliary terminal with a point of opposite potential from said main terminal.

8. I11 a watthour meter, a main terminal with a bushing, a metallic member in said bushing and insulated from said terminal, metallic means mounted on said member and extending from said bushing, and a metal bar detachably connected to said metallic means and to a point of opposite potential from said main terminal.

9. In a watthour meter, a terminal with a. bushing, a-metal member in' said. bushing and insulated from said terminal, a sleeve with a binding screw mounted on said member, and electricity conducting means removably connected to said sleeve with said binding screw and to a terminal of opposite potential than the first terminal.

10. In a watthour meter, a device comprising a main terminal housed in a bushing, a metal ring supported in said bushing and separated from said terminal by an insulating gasket, a binding screw extending in said terminal for holding a terminal wire extending through said ring and said gasket, an auxiliary bushing mounted in said first bushing, an auxiliary terminal mounted in said auxiliary bushing, said auxiliary terminal being removably fastened to said ring and containing a binding screw, and a metal bar held by the last said binding screw and attached to a point in said meter for imparting to said auxiliary terminal andsaid ring a potential different from the potential of said main terminal.

11. In a watthour meter having a terminal box with terminals'therein, one of said terminals comprising a bushing, a main terminal mounted in said bushing, a metal ring mounted in said bushing and insulated from said main terminal, a terminal wire extending through said ring and connected in said main terminal, said ring being but slightly larger than said terminal wire to engage a shunt wire when inserted between it and said terminal wire, an auxiliary terminal connected to said ring, and an electric conductor extending from said auxiliary terminal to a terminal of opposite potential from said main terminal.

12. In a watthour meter having a terminal box with line terminals and load terminals housed therein, one of the load terminals comprising a bushing, a main terminal mounted therein and having a part extending therefrom for connection to the load side of the current coil of said meter, a metal ring mounted in said bushing, insulating means placed between said main terminal and ring, a binding screw extending into said, main terminal for holding a. terminal wire extending with insulation through said ring, said ring providing a small space between its interior and said insulated terminal wire, an auxiliary terminal connected to said ring, an auxiliary bushing surrounding said auxiliary terminal, and an insulated bar extending from said auxiliary terminal to a line terminal, for imparting to said auxiliary terminal and ring apotential difierent from that of said main terminal.

In testimony whereof I have signed my name to this specification.

FRANK A. KOLB. 

